T Line Full Titanium Brompton incoming!

[FrankCrank]

It's been a long time since I welded any Ti, and that was with orbital welding gear, not 'by hand' as it were. Everything has to be set up perfect to achieve decent, trustworthy welds, way more so than with other metals. QC will be a major factor in all of the production process. Wondering if stainless might be a better option.

 

[Schwinnsta]

Why would stainless better?

 

[FrankCrank]

Stainless is easier to weld. It is readily available. Is a lot cheaper. Similar tube sizes for say, a Brompton clone, can be used. No paint needed. A metallurgist would be needed to comment on the relative strengths when compared to other steel types. Regular DF bikes have been built in stainless, but maybe an issue for a folding bikes, ie fatigue failure in the hinge area? - not sure on this one. I built my recumbent trike and LWB in stainless - no issues. One thing I remember from my career as a welder, many moons ago, the machinists hated Ti - a very tough material on the lathe trying to prep up a weld joint. Anyways, all grist to the mill

 

[IanSmithCSE]

Good morning,

Are titanium welding and machining skills along with equipment an issue as the P Line already has a titanium rear frame and forks?

I am not a Brompton guru and have no idea if these parts are made in-house or bought in and if the main frame would be made in the same place.

Bye

Ian

 

[berlinonaut]

Are titanium welding and machining skills along with equipment an issue as the P Line already has a titanium rear frame and forks?
I am not a Brompton guru and have no idea if these parts are made in-house or bought in and if the main frame would be made in the same place.

These parts used to be bought from external companies in Russia and China but today they are made in the uk by a subsidiary of Brompton the Brompton Fletcher Limited (it is a joint venture between Brompton and Fletcher to be precise). It is a smallish company and they do the Brompton ti-parts for a couple of years already. They should have the knowledge to do a full frame, too.

 

[rogerzilla]

There have been Ti fork issues. The usual issue is that the steerer stretches where the stem is expanded (they really need to lose that quill stem). You can buy reinforcing sleeves for the steerer.

The main frame (and stem, if they do that too) is far more challenging because of its size, the hinged joints and the much higher bending and twisting stresses.

My guess is that it will be priced to cover at least one warranty replacement. That's not unusual practice in the bike industry.

 

[IanSmithCSE]

Good morning,

These parts used to be bought from external companies in Russia and China but today they are made in the uk by a subsidiary of Brompton the Brompton Fletcher Limited (it is a joint venture between Brompton and Fletcher to be precise). It is a smallish company and they do the Brompton ti-parts for a couple of years already. They should have the knowledge to do a full frame, too.

Thanks for this.

https://find-and-update.company-inf...any/08783922/persons-with-significant-control and https://www.cwfletcher.co.uk/

Seems to suggest that they may have some capabilities in titanium.

Bye

Ian

 

[T4tomo]

Why would stainless better?

Indeed, other than being shiny, it doesn't offer any advantage over the regular painted steel mainframe and it isn't any lighter, which is the aim of the game.

 

[rogerzilla]

Indeed, other than being shiny, it doesn't offer any advantage over the regular painted steel mainframe and it isn't any lighter, which is the aim of the game.

Reynolds 953, their lightest tubeset*, is stainless. The top Moulton models are also stainless (although there are reports of them rusting).

*although they can't currently supply it due to material shortages

 

[berlinonaut]

There have been Ti fork issues. The usual issue is that the steerer stretches where the stem is expanded (they really need to lose that quill stem). You can buy reinforcing sleeves for the steerer.

These issues were related to the classic expander cone that Brompton used. In 2019 they switched the cone type to (sloped) wedge and the problem seems to be gone (not totally sure about the correct words - I am at the limit of my English here ). Also interesting that those issues arose more or less mostly after the move to the ti-production back to the UK. There have been older bikes with those issues, mainly they became public after like 2017. Also, Brompton at that time published different torque levels for steel and ti bikes - until then this was not the case.

My guess is that it will be priced to cover at least one warranty replacement. That's not unusual practice in the bike industry.

Do you have any examples?

 

[Cycleops]

Indeed, other than being shiny, it doesn't offer any advantage over the regular painted steel mainframe and it isn't any lighter, which is the aim of the game.

I'd say the aim of the game is the bling factor and exclusivity. After all how often do you have to carry it ?

 

[T4tomo]

Reynolds 953, their lightest tubeset*, is stainless. The top Moulton models are also stainless (although there are reports of them rusting).

*although they can't currently supply it due to material shortages

Hmm interesting....

Supply issue aside, maybe brommie should be investigating if they can make a thinner walled (and hence lighter) mainframe from 953 steel that still gives the required strength & durability.

 

[T4tomo]

I'd say the aim of the game is the bling factor and exclusivity. After all how often do you have to carry it ?

Really, how often do you carry a regular road bike - weight seems to be pretty important in the marketing / buying decision / performance etc etc of those, its no different with a Brompton, infact even more important as you do carry it sometimes and man handle it on and off train etc for the reasonable proportion who commute on them, take them on canal boats / campervans / caravans etc

Why would they market the current part titanium titanium as "superlight" rather than "superexclusive" or "superbling"?

 

[Cycleops]

Weight is only important on any bike when climbing hills, I'd have thought even you might know that. Lifting it on and off a train takes but a few minutes.
Bromptons are bought as mainly commuter city bikes, not general purpose sports bikes.
As for naming I doubt Mr Double barrel in marketing wouldn't find much favour with your suggested names.

 

[berlinonaut]

I'd say the aim of the game is the bling factor and exclusivity. After all how often do you have to carry it ?

On a daily basis, on regular days at least four times a day, in total about 350 stairs. So yes, weight does matter to me on a Brompton. Bling on the other hand is not at all relevant to me.